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1
Jordan, Christopher E. „Scale effects in the kinematics and dynamics of swimming leeches“. Canadian Journal of Zoology 76, Nr. 10 (01.10.1998): 1869–77. http://dx.doi.org/10.1139/z98-131.
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Slender-bodied organisms swimming with whole-body undulations exhibit what appears to be a high degree of kinematic parameter conservation, which is independent of body size. However, organisms of very different sizes swim in fundamentally different physical realms, owing to the relative scaling of viscous and inertial fluid stresses as a function of size and speed. In light of the size-dependent fluid forces, the kinematic constancy suggests three hypotheses: (1) swimming organisms adopt a single "ideal" swimming mode requiring the modification of muscle forces or motor patterns through ontogeny, (2) swimming kinematics are determined predominantly by the passive mechanical interaction of the body and the fluid, resulting in a single swimming mode independent of absolute body size, or (3) while undulatory swimming kinematics may be similar between organisms, there are important size-dependent kinematic differences. In this study, I address this issue by examining the swimming kinematics and dynamics of the medicinal leech Hirudo medicinalis L. as a function of body size. Over a 5-fold increase in body length, the relative amplitude of body undulations during swimming did not change; however, swimming speed, propulsive wave speed, and propulsive wave frequency all decreased, while propulsive wave number increased slightly, strongly supporting hypothesis 2. To determine the source of the observed size-dependent swimming kinematics, I manipulated the dynamic viscosity of the organism's fluid environment to alter the constraints placed on swimming behavior by the physical surroundings. In the elevated-viscosity treatment, all kinematic parameters changed in the opposite direction to that predicted by hypothesis 2, rejecting both the idea that swimming kinematics are simply determined by passive mechanical interactions and that leeches have a target swimming mode under active control.
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Irmak, Özgür, und Ekim O. Orhan. „Kinematic analysis of new and used reciprocating endodontic motors in 2 different modes“. International Journal of Artificial Organs 41, Nr. 1 (08.10.2017): 17–22. http://dx.doi.org/10.5301/ijao.5000640.
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Purpose: The actual reciprocating angles of endodontic motors might differ from the manufacturers’ set values. This study analyzed the effect of clinical usage on the kinematics of reciprocating endodontic motors with 2 different reciprocal modes. Methods: 1 new and 3 used reciprocating endodontic motors (X-Smart Plus, Dentsply Maillefer) with 2 different reciprocating modes, WaveOne mode (W-mode) or Reciproc mode (R-mode), were analyzed. An angle measurement disc was inserted into a contra-angle. Reciprocating motions were recorded with a high-speed camera at 1,200 fps and analyzed on a computer. The following kinematic parameters were calculated: duration of each reciprocating motion, engaging and disengaging angles, cycle rotational speeds, engaging and disengaging rotational speeds, net cycle angle, total cycle angle, and number of cycles to complete full rotation. One-way ANOVA and Kruskal-Wallis test followed by multiple comparison tests were used for statistical analysis (p = 0.05). Results: In W-mode, the actual engaging angles of all used and new motors were different from the manufacturer’s set values (p<0.0001), whereas there was no difference between actual engaging angles among the motors (p>0.05). In R-mode, the actual engaging angles of all used and new motors were similar to the manufacturers’ set values (p>0.05). There was no difference between the actual engaging angles among motors (p>0.05). Both the W-mode and R-mode showed statistically different values of actual disengaging angles for all used and new motors when compared with the manufacturers’ set value (p<0.0001). Conclusions: This study confirmed that the actual kinematics of reciprocating endodontic motors differ from the manufacturers’ set values. Some kinematic parameters were influenced by the clinical usage of the motors.
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He, Xiuyun, Xianwen Kong, Damien Chablat, Stéphane Caro und Guangbo Hao. „Kinematic analysis of a single-loop reconfigurable 7R mechanism with multiple operation modes“. Robotica 32, Nr. 7 (22.01.2014): 1171–88. http://dx.doi.org/10.1017/s0263574713001197.
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SUMMARYThis paper presents a novel one-degree-of-freedom (1-DOF) single-loop reconfigurable 7R mechanism with multiple operation modes (SLR7RMMOM), composed of seven revolute (R) joints, via adding a revolute joint to the overconstrained Sarrus linkage. The SLR7RMMOM can switch from one operation mode to another without disconnection and reassembly, and is a non-overconstrained mechanism. The algorithm for the inverse kinematics of the serial 6R mechanism using kinematic mapping is adopted to deal with the kinematic analysis of the SLR7RMMOM. First, a numerical method is applied and an example is given to show that there are 13 sets of solutions for the SLR7RMMOM, corresponding to each input angle. Among these solutions, nine sets are real solutions, which are verified using both a computer-aided design (CAD) model and a prototype of the mechanism. Then an algebraic approach is also used to analyse the mechanism and same results are obtained as the numerical one. It is shown from both numerical and algebraic approaches that the SLR7RMMOM has three operation modes: a translational mode and two 1-DOF planar modes. The transitional configurations among the three modes are also identified.
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Ter-Martirosyan, Zaven, Eugene Sobolev und Armen Ter-Martirosyan. „Rheological Properties of Sandy Soils“. Advanced Materials Research 1073-1076 (Dezember 2014): 1673–79. http://dx.doi.org/10.4028/www.scientific.net/amr.1073-1076.1673.
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Modern models of soils to describe elastic-viscoplastic properties do not always lead to the desired results , especially when it is necessary to take into account the time factor. In particular, one cannot always describe the rheological model and creep and relaxation , as well as get extreme at kinematic mode loading. This is due to the fact that the deformation in the soil medium is accompanied by complex physical and physico-chemical phenomena , changes in the orientation of each mineral particles in space and time , their mutual offset seal ( hardening ) and decompression ( softening ) . Quantitative assessment of buildings and facilities associated with the calculation of the stress - strain state ( SSS ) foundation soils subject to numerous factors , including the physical feature of the power and influence ( statics, kinematics, dynamics ) and mechanical properties of soils under such effects ( creep , ductility ) .In the present paper the results of scientific studies of the rheological properties of sandy soils. The purpose of these studies - determination of viscosity sandy soils kinematic and dynamic triaxial test mode. A technique for determining the viscosity of soils results in triaxial kinematic mode (with speed control vertical movements). The paper considers the problem of estimating the impact of the dynamic loads on the viscosity of sandy soils.
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Mohammed Elawady, Wael, Yassine Bouteraa und Ahmed Elmogy. „An Adaptive Second Order Sliding Mode Inverse Kinematics Approach for Serial Kinematic Chain Robot Manipulators“. Robotics 9, Nr. 1 (03.01.2020): 4. http://dx.doi.org/10.3390/robotics9010004.
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The problem of inverse kinematics is essential to consider while dealing with the robot’s mechanical structure in almost all applications. Since the solution of the inverse kinematics problem is very complex, many research efforts have been working towards getting the approximate solution of this problem. However, for some applications, working with the approximate robot’s model is neither sufficient nor efficient. In this paper, an adaptive inverse kinematics methodology is developed to solve the inverse kinematics problem in such a way that compensate for unknown uncertainty in the Jacobian matrix of the serial kinematic chain robot manipulators. The proposed methodology is based on continuous second order sliding mode strategy (CSOSM-AIK). The salient advantage of the CSOSM-AIK approach is that it does not require the availability of the kinematics model or Jacobian matrix of the robot manipulators from joint space variables to Cartesian space variables. The global stability of the closed-loop system with CSOSM-AIK methodology is proven using the Lyapunov theorem. In order to demonstrate the robustness and effectiveness of the proposed methodology, some simulations are conducted.
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Sum Wu, Kit, Jerome Nowak und Kenneth S. Breuer. „Scaling of the performance of insect-inspired passive-pitching flapping wings“. Journal of The Royal Society Interface 16, Nr. 161 (Dezember 2019): 20190609. http://dx.doi.org/10.1098/rsif.2019.0609.
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Flapping flight using passive pitch regulation is a commonly used mode of thrust and lift generation in insects and has been widely emulated in flying vehicles because it allows for simple implementation of the complex kinematics associated with flapping wing systems. Although robotic flight employing passive pitching to regulate angle of attack has been previously demonstrated, there does not exist a comprehensive understanding of the effectiveness of this mode of aerodynamic force generation, nor a method to accurately predict its performance over a range of relevant scales. Here, we present such scaling laws, incorporating aerodynamic, inertial and structural elements of the flapping-wing system, validating the theoretical considerations using a mechanical model which is tested for a linear elastic hinge and near-sinusoidal stroke kinematics over a range of scales, hinge stiffnesses and flapping frequencies. We find that suitably defined dimensionless parameters, including the Reynolds number, Re , the Cauchy number, Ch , and a newly defined ‘inertial-elastic’ number, IE, can reliably predict the kinematic and aerodynamic performance of the system. Our results also reveal a consistent dependency of pitching kinematics on these dimensionless parameters, providing a connection between lift coefficient and kinematic features such as angle of attack and wing rotation.
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Sen, P. K., und D. S. Arora. „On the stability of laminar boundary-layer flow over a flat plate with a compliant surface“. Journal of Fluid Mechanics 197 (Dezember 1988): 201–40. http://dx.doi.org/10.1017/s0022112088003234.
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The problem has been examined using a kinematic model for wall pliability, wherein a kinematic postulation of the wall boundary conditions is made. A form of the normalized wall-displacement and its phase are used as additional parameters in an extended eigenvalue problem. Using this technique the entire gamut of possibilities regarding stability of flow past (normally) pliable walls can be examined, yet without recourse to any specific material properties for the wall. Rather, the results based on the kinematic model can be used to back-calculate the material properties corresponding to any chosen model for the dynamics of the wall. A sample back calculation is discussed herein for the Benjamin–Landahl wall model, and based on this some predictions are made regarding both stabilization of the flow and physical realizability of modes. It is believed that the kinematic model will prove useful in further understanding of the problem, and in the design of stabilizing coatings.The results show that there are three important ‘mode classes’ (distinct from ‘modes’), namely the Tollmien–Schlichting (TS), resonant (R) and Kelvin–Helmholtz (KH). Whereas the TS and R mode classes broadly agree with modes bearing similar names as found by earlier workers, the present KH mode class is difficult to classify based on earlier work. Moreover, there are also important transitional mode classes in the regions of bifurcations of the regular mode classes.Two important concepts evolve in connection with the TS and R mode classes, namely the existence of ‘stable pockets’ for the former and ‘unstable pockets’ for the latter. It is also confirmed herein that there are conflicting requirements on the damping d to stabilize TS and R modes. Considering these points it has been suggested that TS and R modes be avoided by keeping soft surfaces as compliant coatings. However, this in turn leads to instabilities from one of the transitional mode classes. It is also seen that a soft surface that is also marginally active (i.e. having a small negative value of d) could render even better stabilization.
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Kim, Hongchul, Young June Shin und Jung Kim. „Kinematic-based locomotion mode recognition for power augmentation exoskeleton“. International Journal of Advanced Robotic Systems 14, Nr. 5 (01.09.2017): 172988141773032. http://dx.doi.org/10.1177/1729881417730321.
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This article presents a kinematic-based method for locomotion mode recognition, for use in the control of an exoskeleton for power augmentation, to implement natural and smooth locomotion transition. The difference in vertical foot position between a foot already in contact with ground and a foot newly in contact with the ground was calculated via kinematics for the entire exoskeleton and used to identify the locomotion mode with other sensor data including data on the knee joint angle and inclination of the thigh, shank, and foot. Locomotion on five different types of terrain—level-ground walking, stair ascent, stair descent, ramp ascent, and ramp descent—were identified using two-layer decision tree classes. An updating process is proposed to improve identification of the transition and accuracy using the foot inclination at the mid-stance. An average identification accuracy of more than 99% was achieved in experiments with eight subjects for single terrains (no terrain transitions) and hybrid terrains. The experimental results show that the proposed method can achieve high accuracy without significant misrecognition and minimize the delay in locomotion mode recognition of the exoskeleton.
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Fang, Jian, Tao Mei, Jianghai Zhao und Tao Li. „A dual-mode online optimization method for trajectory tracking of redundant manipulators“. Industrial Robot: An International Journal 43, Nr. 2 (21.03.2016): 241–52. http://dx.doi.org/10.1108/ir-07-2015-0135.
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Purpose – The purpose of this paper is to present a dual-mode online optimization method (OOM) for trajectory tracking of the redundant manipulators. This method could be used to resolve the problem of the kinematics redundancy effectively when the manipulator moves in a limited space or its movements go through a singular point. Design/methodology/approach – In the proposed method, the physical limits of the manipulator in the torque level is considered as inequality constraints for the optimal scheme. Besides, a dual-mode optimal scheme is developed to yield a feasible input in each control period during the path tracking task of the manipulator, especially when it moves under the limited space or around the singular point. Then, the scheme is formulated as a quadratic programming; the computationally efficient quadratic programming solver based on interior method is formulated to solve the kinematic redundancy problem. Findings – The traditional pseudo inverse method (PIM) for the kinematic resolution to the redundant manipulator has some limitations, such as slow computation speed, unable to take joint physical limits into consideration, etc. Relatively, the OOM could be used to conquer the deficits of the PIM method. Combining with the dual-mode optimal scheme and considering the physical constraints in the torque level, the online method proposed in this paper is more robust and efficient than the existing method. Originality/value – In this paper, dual-mode OOM is first proposed for the resolution of the kinematics redundancy problem. Specific design of its model and the discussion of its performance are also presented in this paper.
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Chen, Jun, Meng-Shi Zhang, Yong-Fang Zhao und Hong-Sheng Zhan. „Kinematic Data Smoothing Using Ensemble Empirical Mode Decomposition“. Journal of Medical Imaging and Health Informatics 4, Nr. 4 (01.08.2014): 540–46. http://dx.doi.org/10.1166/jmihi.2014.1281.
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Zhang, Tinggang, und Lutfi Raad. „An eigen-mode method in kinematic shakedown analysis“. International Journal of Plasticity 18, Nr. 1 (Januar 2002): 71–90. http://dx.doi.org/10.1016/s0749-6419(00)00055-3.
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Parslew, Ben. „Predicting power-optimal kinematics of avian wings“. Journal of The Royal Society Interface 12, Nr. 102 (Januar 2015): 20140953. http://dx.doi.org/10.1098/rsif.2014.0953.
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A theoretical model of avian flight is developed which simulates wing motion through a class of methods known as predictive simulation. This approach uses numerical optimization to predict power-optimal kinematics of avian wings in hover, cruise, climb and descent. The wing dynamics capture both aerodynamic and inertial loads. The model is used to simulate the flight of the pigeon, Columba livia , and the results are compared with previous experimental measurements. In cruise, the model unearths a vast range of kinematic modes that are capable of generating the required forces for flight. The most efficient mode uses a near-vertical stroke–plane and a flexed-wing upstroke, similar to kinematics recorded experimentally. In hover, the model predicts that the power-optimal mode uses an extended-wing upstroke, similar to hummingbirds. In flexing their wings, pigeons are predicted to consume 20% more power than if they kept their wings full extended, implying that the typical kinematics used by pigeons in hover are suboptimal. Predictions of climbing flight suggest that the most energy-efficient way to reach a given altitude is to climb as steeply as possible, subjected to the availability of power.
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Sierra M, Sergio D., Marcela Múnera, Thomas Provot, Maxime Bourgain und Carlos A. Cifuentes. „Evaluation of Physical Interaction during Walker-Assisted Gait with the AGoRA Walker: Strategies Based on Virtual Mechanical Stiffness“. Sensors 21, Nr. 9 (07.05.2021): 3242. http://dx.doi.org/10.3390/s21093242.
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Smart walkers are commonly used as potential gait assistance devices, to provide physical and cognitive assistance within rehabilitation and clinical scenarios. To understand such rehabilitation processes, several biomechanical studies have been conducted to assess human gait with passive and active walkers. Several sessions were conducted with 11 healthy volunteers to assess three interaction strategies based on passive, low and high mechanical stiffness values on the AGoRA Smart Walker. The trials were carried out in a motion analysis laboratory. Kinematic data were also collected from the smart walker sensory interface. The interaction force between users and the device was recorded. The force required under passive and low stiffness modes was 56.66% and 67.48% smaller than the high stiffness mode, respectively. An increase of 17.03% for the hip range of motion, as well as the highest trunk’s inclination, were obtained under the resistive mode, suggesting a compensating motion to exert a higher impulse force on the device. Kinematic and physical interaction data suggested that the high stiffness mode significantly affected the users’ gait pattern. Results suggested that users compensated their kinematics, tilting their trunk and lower limbs to exert higher impulse forces on the device.
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Ding, Wan, Qiang Ruan und Yan-an Yao. „Design and locomotion analysis of a novel deformable mobile robot with two spatial reconfigurable platforms and three kinematic chains“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, Nr. 8 (29.03.2016): 1481–99. http://dx.doi.org/10.1177/0954406216641453.
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A novel five degrees of freedom deformable mobile robot composed of two spatial reconfigurable platforms and three revolute–prismatic–spherical kinematic chains acting in parallel to link the two platforms is proposed to realize large deformation capabilities and multiple locomotion modes. Each platform is an improved deployable single degrees of freedom three-plane-symmetric Bricard linkage. By taking advantage of locomotion collaborating among platforms and kinematic chains, the mobile robot can fold into stick-like shape and possess omnidirectional rolling and worm-like motions. The mechanism design, kinematics, and locomotion feasibility are the main focus. Through kinematics and gait planning, the robot is analyzed to have the capabilities of rolling and turning. Based on its deformation, the worm-like motion performs the ability to overcome narrow passages (such as pipes, holes, gaps, etc.) with large range of variable size. Dynamic simulations with detailed three-dimensional model are carried out to verify the gait planning and provide the variations of essential motion and dynamic parameters in each mode. An experimental robotic system with servo and pneumatic actuation systems is built, experiments are carried out to verify the validity of the theoretical analysis and the feasibility of the different locomotion functions, and its motion performances are compared and analyzed with collected data.
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Li, Si Yi, und Ya Ping Yang. „The Series Combination of Cycloid Tooth Profile Planetary Mechanism and Screw Mechanism for Linear Drivers“. Advanced Materials Research 308-310 (August 2011): 2191–94. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.2191.
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A combined mechanism, which cycloid tooth profile planetary mechanism and screw mechanism are connected in series, can convert the input-component’s high-speed rotary motion to output-component’s low-speed reciprocating linear motion. Base on that mechanism, a linear drivers was developed. And it is composed by electric motor, eccentric shaft, cycloid-plate, screw & nut, and so on. Because an intermediate transmission mode used rolling-body is applied in the contact surfaces among the kinematic pairs, the drivers’ stability and transmission efficiency are enhanced through improving kinematic pairs’ friction state and reducing parts abrasion. In the paper, it is emphasis discussed that the kinematics and main parameters’ computational method for cycloid tooth profile planetary mechanism.
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Hilker, Michael, Carlos Eduardo Barbosa, Tom Richtler, Lodovico Coccato, Magda Arnaboldi und Claudia Mendes de Oliveira. „A 3D view of the Hydra I galaxy cluster core - I. Kinematic substructures“. Proceedings of the International Astronomical Union 10, S309 (Juli 2014): 221–22. http://dx.doi.org/10.1017/s1743921314009715.
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AbstractWe used FORS2 in MXU mode to mimic a coarse ‘IFU’ in order to measure the 3D large-scale kinematics around the central Hydra I cluster galaxy NGC 3311. Our data show that the velocity dispersion field varies as a function of radius and azimuthal angle and violates point symmetry. Also, the velocity field shows similar dependence, hence the stellar halo of NGC 3311 is a dynamically young structure. The kinematic irregularities coincide in position with a displaced diffuse halo North-East of NGC 3311 and with tidal features of a group of disrupting dwarf galaxies. This suggests that the superposition of different velocity components is responsible for the kinematic substructure in the Hydra I cluster core.
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Liang, Xichang, Yi Wan und Chengrui Zhang. „Task Space Trajectory Tracking Control of Robot Manipulators with Uncertain Kinematics and Dynamics“. Mathematical Problems in Engineering 2017 (2017): 1–19. http://dx.doi.org/10.1155/2017/4275201.
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To improve the tracking precision of robot manipulators’ end-effector with uncertain kinematics and dynamics in the task space, a new control method is proposed. The controller is based on time delay estimation and combines with the nonsingular terminal sliding mode (NTSM) and adaptive fuzzy logic control scheme. Kinematic parameters are not exactly required with the consideration of kinematic uncertainties in the controller. No dynamic models or numerous parameters of the robot manipulator system are required with the use of TDE. Thus, the controller is simple structure and suitable for practical applications. Furthermore, errors caused by time delay estimation are compensated by the adaptive fuzzy nonsingular terminal sliding mode scheme. The simulation is performed on a 2-DOF robot manipulator with three cases in the task space. The results show that the proposed controller provides faster convergence rate and higher tracking precision than TDE based NTSM and improved TDE based NTSM controller.
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Tomasz, Hadaś. „GNSS-Warp Software for Real-Time Precise Point Positioning“. Artificial Satellites 50, Nr. 2 (01.06.2015): 59–76. http://dx.doi.org/10.1515/arsa-2015-0005.
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Abstract On April 1, 2013 IGS launched the real-time service providing products for Precise Point Positioning (PPP). The availability of real-time makes PPP a very powerful technique to process GNSS signals in real-time and opens a new PPP applications opportunities. There are still, however, some limitations of PPP, especially in the kinematic mode. A significant change in satellite geometry is required to efficiently de-correlate troposphere delay, receiver clock offset, and receiver height. In order to challenge PPP limitations, the GNSS-WARP (Wroclaw Algorithms for Real-time Positioning) software has been developed from scratch at Wroclaw University of Environmental and Life Science in Poland. This paper presents the GNSS-WARP software itself and some results of GNSS data analysis using PPP and PPP-RTK (Real-Time Kinematic) technique. The results of static and kinematic processing in GPS only and GPS + GLONASS mode with final and real-time products are presented. Software performance validation in postprocessing mode confirmed that the software can be considered as a state-ofthe- art software and used for further studies on PPP algorithm development. The real-time positioning test made it possible to assess the quality of real-time coordinates, which is a few millimeters for North, East, Up in static mode, a below decimeter in kinematic mode. The accuracy and precision of height estimates in kinematic mode were improved by constraining the solution with an external, near real-time troposphere model. The software also allows estimation of real-time ZTD, however, the obtained precision of 11.2 mm means that further improvements in the software, real-time products or processing strategy are required.
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Kornienko, L. S., T. V. Klykova, Nikolai V. Kravtsov, Vladimir A. Sidorov, A. M. Susov und Yu P. Yatsenko. „Kinematic mode locking in a cw YAG:Nd ring laser“. Soviet Journal of Quantum Electronics 16, Nr. 12 (31.12.1986): 1637–42. http://dx.doi.org/10.1070/qe1986v016n12abeh008514.
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Schütte, Jan, und Walter Sextro. „Tire Wear Reduction Based on an Extended Multibody Rear Axle Model“. Vehicles 3, Nr. 2 (18.05.2021): 233–56. http://dx.doi.org/10.3390/vehicles3020015.
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To analyze the influence of suspension kinematics on tire wear, detailed simulation models are required. In this study, a non-linear, flexible multibody model of a rear axle system is built up in the simulation software MSC Adams/View. The physical model comprises the suspension kinematics, compliance, and dynamics as well as the non-linear behavior of the tire using the FTire model. FTire is chosen because it has a separate tire tread model to compute the contact pressure and friction force distribution in the tire contact patch. To build up the simulation model, a large amount of data is needed. Bushings, spring, and damper characteristics are modeled based on measurements. For the structural components (e.g., control arms), reverse engineering techniques are used. The components are 3D-scanned, reworked, and included as a modal reduced finite element (FE)-model using component mode synthesis by Craig–Bampton. Finally, the suspension model is validated by comparing the simulated kinematic and compliance characteristics to experimental results. To investigate the interaction of suspension kinematics and tire wear, straight line driving events, such as acceleration, driving with constant velocity, and deceleration, are simulated with different setups of wheel suspension kinematics. The influence of the setups on the resulting friction work between tire and road is examined, and an exemplarily calculation of tire wear based on a validated FTire tire model is carried out. The results demonstrate, on the one hand, that the chosen concept of elasto-kinematic axle leads to a relatively good match with experimental results and, on the other hand, that there are significant possibilities to reduce tire wear by adjusting the suspension kinematics.
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Koh, H. M., und R. B. Haber. „Elastodynamic Formulation of the Eulerian-Lagrangian Kinematic Description“. Journal of Applied Mechanics 53, Nr. 4 (01.12.1986): 839–45. http://dx.doi.org/10.1115/1.3171868.
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An extension of the Eulerian-Lagrangian kinematic description (Haber, 1984) to elastodynamic problems is presented. Expressions are derived for field variables and material time derivatives using the new kinematic description. The variational equation of motion is written in a weak form suitable for use with isoparametric finite elements. The new kinematic model allows a finite element mesh to continuously adjust for changes in the structural geometry, material interfaces, or the domain of the boundary conditions without a discrete remeshing process. Applications of the new model to mode I dynamic crack propagation demonstrates its advantages over moving mesh methods based on conventional Lagrangian kinematic models. Numerical results show excellent agreement with analytic predictions.
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Song, Meng Jun, Cheng Jun Ding und Chang Juan Yu. „Workspace Analyzing for Hybrid Serial-Parallel Mechanism of a New Bionic Quadruped Robot“. Applied Mechanics and Materials 713-715 (Januar 2015): 837–40. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.837.
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In this paper, a new bionic quadruped robot was proposed by us. The mechanism of robot we analyzed is as a hybrid series-parallel mechanism, so a new methods for constructing the kinematic model of the bionic quadruped robot very quickly and efficiently was introduced. we analyzed the workspace of the legged mechanism by using geometric composition method and numerical analysis method in the following section. Furthermore, the kinematic model of the parallel mechanism of the multi-motion mode bionic quadruped robot was constructed when the robot was in the stance phase, we also construct and solve the inverse kinematic model of the parallel mechanism of the robot, and the simulation results provide a better method for the robot’s workspace analyzing;Finally, the simulation experiment showed that the method we presented above could provide a good support for the multi-motion mode bionic quadruped robot walking smoothly and automatically.
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Kurkina, Oxana, Tatyana Talipova, Tarmo Soomere, Ayrat Giniyatullin und Andrey Kurkin. „Kinematic parameters of internal waves of the second mode in the South China Sea“. Nonlinear Processes in Geophysics 24, Nr. 4 (19.10.2017): 645–60. http://dx.doi.org/10.5194/npg-24-645-2017.
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Abstract. Spatial distributions of the main properties of the mode function and kinematic and non-linear parameters of internal waves of the second mode are derived for the South China Sea for typical summer conditions in July. The calculations are based on the Generalized Digital Environmental Model (GDEM) climatology of hydrological variables, from which the local stratification is evaluated. The focus is on the phase speed of long internal waves and the coefficients at the dispersive, quadratic and cubic terms of the weakly non-linear Gardner model. Spatial distributions of these parameters, except for the coefficient at the cubic term, are qualitatively similar for waves of both modes. The dispersive term of Gardner's equation and phase speed for internal waves of the second mode are about a quarter and half, respectively, of those for waves of the first mode. Similarly to the waves of the first mode, the coefficients at the quadratic and cubic terms of Gardner's equation are practically independent of water depth. In contrast to the waves of the first mode, for waves of the second mode the quadratic term is mostly negative. The results can serve as a basis for expressing estimates of the expected parameters of internal waves for the South China Sea.
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Zhang, Hongwen, Zhanxia Zhu, Biwei Tang und Jianping Yuan. „The establishment and verification of kinematic equation of all link centroid of the manipulator mounted on a satellite“. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, Nr. 5 (26.04.2018): 1801–19. http://dx.doi.org/10.1177/0954410018763926.
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When using space robot to capture target like failed satellite, the force impulse between the target and the end-effector of space robot will load the base satellite with additional momentum abruptly. When capture happens, the pre-impact configuration can influence augmentations of partial momentum of the base and the manipulator. In order to realize a pre-impact configuration, which can reduce the partial momentum augmentations, the control of all link centroid together with end-effector by path planning is very important. In this paper, we establish a basic velocity kinematic equation for all link centroid, which describes the basic linear kinematic relationship between the linear velocity of all link centroid and linear and angular velocities of the base, joint angular velocity of the manipulator, where this basic velocity kinematic equation can be developed into kinematic equations for all link centroid under different kinds of working modes such as free-floating working mode. All link centroid can be controlled by path planning with this equation. Besides, velocity kinematic equation for all link centroid of space robot under a specific working mode is similar to the velocity kinematic equation for end-effector of space robot under the same working mode, so all link centroid can be controlled together with end-effector by path planning. We have derived velocity kinematic equations for all link centroid of space robot with a free-floating base and a fixed base. Both of them are verified by numerical simulations. The motions of position and attitude of the base and the manipulator end caused by all link centroid motion are also shown by simulation study. We also realize the simultaneous path tracking of all link centroid and end-effector for a fixed base space robot.
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Qu, Haibo, Yuefa Fang, Sheng Guo und Wei Ye. „A novel 4-UPU translational parallel mechanism with fault-tolerant configurations“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, Nr. 16 (24.02.2014): 3006–18. http://dx.doi.org/10.1177/0954406214525366.
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This paper aims at designing a pure translational parallel mechanism constructed by UPU (universal-prismatic-universal joint) kinematic limbs. First, the typical problem of unexpected rotations is pointed out from analyzing the typical 3-UPU parallel mechanism, and the reason for unexpected rotations of parallel mechanism constructed by UPU kinematic limbs is analyzed. Then, in order to design a pure translational parallel mechanism constructed by UPU without the unexpected rotations, the 2-UPU single loop is chosen as the basic structure to construct the 4-UPU translational parallel mechanism. Each 2-UPU single loop can be used to constrain a rotation about an axis of the linear complexes, which defined the unexpected rotations. Therefore, a novel type of 4-UPU pure translational parallel mechanism with redundant actuations is proposed. Since the existence of redundantly actuated kinematic limb, this proposed parallel mechanism possesses analytical forward kinematics, and its singularity can be avoided completely. Finally, the workspace and fault-tolerant performance are analyzed. When the proposed 4-UPU parallel mechanism is located in a fault-tolerant configuration, the moving platform can still possess movable ability to realize the given task even if one kinematic limb is in locked-joint failure mode, and the fault-tolerant workspace is obtained.
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Zhu, Xiao Rong, Hui Ping Shen und Wei Zhu. „Optimal Kinematic Design of a 2-DOF Planar Parallel Manipulator“. Applied Mechanics and Materials 44-47 (Dezember 2010): 1843–47. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.1843.
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This paper addresses geometry design and operating mode optimum design of a new kind of 2-DOF parallel manipulator actuated horizontally by linear actuators. The forward and inverse kinematics of this manipulator are derived. The four groups of inverse solution correspond to four different operating modes which cannot transit to each other smoothly. The workspace and the singularity trajectory of each mode are discussed. Based on the desired workspace, the geometry of the mechanism is determined. The operating mode of the mechanism is optimized according to distributing of all global and local performance indices on the workspace. The results are very useful for the design and application of the new manipulator with multiple forward and inverse solutions.
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Misslisch, H., und D. Tweed. „Neural and Mechanical Factors in Eye Control“. Journal of Neurophysiology 86, Nr. 4 (01.10.2001): 1877–83. http://dx.doi.org/10.1152/jn.2001.86.4.1877.
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Soft tissue “pulleys” in the orbit alter the paths of the eye muscles in a way that may simplify the brain's work in implementing Listing's law, i.e., in holding ocular torsion at zero. But Listing's law does not apply to some oculomotor systems, such as the vestibuloocular reflex (VOR), which shows a different kinematic pattern. To explain this different pattern, some authors have assumed that the pulleys must adopt a different configuration, retracting along their muscles when the eye switches from Listing's law to VOR mode. The proposed retraction has not so far been observed, although the pulleys do move in other ways. We show that the hypothetical retraction of the pulleys would not in fact explain the full kinematic pattern seen in the VOR. But this pattern can be explained entirely on the basis of pulley positions and motions that have actually been observed. If one takes into account the neural processing within the VOR, specifically the fact that the reflex is weak in the torsional dimension, then a single mode of pulley action can serve both vestibuloocular kinematics and Listing's law.
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Tan, Yue Sheng. „Mathematical Model for the Effect of Dynamic Parameter Posed on Free Floating Space Manipulator’s Kinematic Accuracy“. Advanced Materials Research 216 (März 2011): 254–60. http://dx.doi.org/10.4028/www.scientific.net/amr.216.254.
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Aiming at kinematic accuracy and its’ error sources of a free floating space robot, a mathematical kinematic error model based on the concept of virtual manipulator and screw theory is proposed in this paper for a free-floating space robot. Based on screw theory, structural parameters in the form of motion screw and their error expressions derived from various error sources are deduced. The effect of mass error, CM (Center of Mass) error and structural parameter error on the kinematic accuracy of the free-floating space manipulator is analyzed. A simulation is demonstrated for verifying the correctness of the kinematic error model and the effect of various error sources on the free-floating space robot. The error model and the result deriving from analyzing are vital for studying the kinematic accuracy of the space manipulator when it is under a free-floating mode, and for controlling and assigning various errors when a space robot is developed.
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Choi, Young-Kiu, Jin-Hyun Park, Hyun-Sik Kim und Jung Hwan Kim. „Optimal trajectory planning and sliding mode control for robots using evolution strategy“. Robotica 18, Nr. 4 (Juli 2000): 423–28. http://dx.doi.org/10.1017/s0263574799002118.
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Although robots have some kinematic and dynamic constraints such as the limits of the position, velocity, acceleration, jerk, and torque, they should move as fast as possible to increase the productivity. Researches on the minimum-time trajectory planning and control based on the dynamic constraints assume the availability of full dynamics of robots. However, the dynamic equation of robot may not often be exactly known. In this case, the kinematic approach for the minimum-time trajectory planning is more meaningful. We also have to construct a controller to track precisely the minimum-time trajectory. But, finding a proper controller is also difficult if we do not know the explicit dynamic equations of a robot.This paper describes an optimization of trajectory planning based on a kinematic approach using the evolution strategy (ES), as well as an optimization of a sliding mode tracking controller using ES for a robot without dynamic equations.
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Song, Meng Jun, Cheng Jun Ding, Xu Long Wang, Yi Zhou und Hai Song Zhou. „Research on Kinematic for the Mechanism of Wheel-Leg Mobile Robot with Multi-Sports Mode“. Advanced Materials Research 1044-1045 (Oktober 2014): 850–53. http://dx.doi.org/10.4028/www.scientific.net/amr.1044-1045.850.
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Based on the walking mechanism and the researching method for the serial-parallel mechanism, one multi-sports mode wheel-leg mobile robot is proposed in this paper; Firstly, the serial mechanism model of one leg is constructed, and the method for constructing the kinematic model of the single leg mechanism is studied; Secondly, based on the study of the single leg mechanism, the kinematic model of the parallel mechanism of the multi-sports mode wheel-leg robot is further constructed when the robot is in the support state; Finally, based on the methods and theories discussed above, the experimental prototype mobile robot is constructed, so feasibility of the proposed method is verified.
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Liu, Haixiao, Yancheng Yang und Jinsong Peng. „A Unified Model for Analyzing Comprehensive Behaviors of Deepwater Anchors“. Journal of Marine Science and Engineering 9, Nr. 8 (23.08.2021): 913. http://dx.doi.org/10.3390/jmse9080913.
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Anchors may exhibit various complicated behaviors in the seabed, especially for deepwater anchors including gravity installed anchors (GIAs) and drag embedment plate anchors (drag anchors), stimulating the development of an efficient analytical tool that applies to a variety of anchors. The present paper introduces a unified model for analyzing different anchor behaviors in both clay and sand, consisting of unified concepts, mechanical models, and analytical procedure. The kinematic behaviors of the anchors are classified uniformly as three types, i.e., diving, pulling out, and keying. By utilizing the least-force principle, various anchor properties, such as the ultimate pullout capacity (UPC), failure mode, movement direction, embedment loss, and kinematic trajectory, can all be determined by the combination and analysis of the three behaviors. Applications of the model are demonstrated summarily, by solving the UPC and the failure mode of anchor piles and suction anchors, the kinematic trajectory of drag anchors in a single soil layer or layered soils, the maximum embedment loss (MEL) of suction embedded plate anchors (SEPLAs) and OMNI-Max anchors, and the kinematic behavior of OMNI-Max anchors. Compared to existing theoretical methods, this unified model shows strong applicability and potentiality in solving a variety of behaviors and properties of different anchors under complicated seabed conditions.
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Rabbou, Mahmoud Abd, und Ahmed El-Rabbany. „PPP Accuracy Enhancement Using GPS/GLONASS Observations in Kinematic Mode“. Positioning 06, Nr. 01 (2015): 1–6. http://dx.doi.org/10.4236/pos.2015.61001.
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Gillis, G. „Anguilliform locomotion in an elongate salamander (Siren intermedia): effects of speed on axial undulatory movements“. Journal of Experimental Biology 200, Nr. 4 (01.02.1997): 767–84. http://dx.doi.org/10.1242/jeb.200.4.767.
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Many workers interested in the mechanics and kinematics of undulatory aquatic locomotion have examined swimming in fishes that use a carangiform or subcarangiform mode. Few empirical data exist describing and quantifying the movements of elongate animals using an anguilliform mode of swimming. Using high-speed video, I examine the axial undulatory kinematics of an elongate salamander, Siren intermedia, in order to provide data on how patterns of movement during swimming vary with body position and swimming speed. In addition, swimming kinematics are compared with those of other elongate vertebrates to assess the similarity of undulatory movements within the anguilliform locomotor mode. In Siren, most kinematic patterns vary with longitudinal position. Tailbeat period and frequency, stride length, Froude efficiency and the lateral velocity and angle of attack of tail segments all vary significantly with swimming speed. Although swimming speed does not show a statistically significant effect on kinematic variables such as maximum undulatory amplitude (which increases non-linearly along the body), intervertebral flexion and path angle, examination of the data suggests that speed probably has subtle and site-specific effects on these variables which are not detected here owing to the small sample size. Maximum lateral displacement and flexion do not coincide in time within a given tailbeat cycle. Furthermore, the maximum orientation (angle with respect to the animal's direction of forward movement) and lateral velocity of tail segments also do not coincide in time. Comparison of undulatory movements among diverse anguilliform swimmers suggests substantial variation across taxa in parameters such as tailbeat amplitude and in the relationship between tailbeat frequency and swimming speed. This variation is probably due, in part, to external morphological differences in the shape of the trunk and tail among these taxa.
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Cook, A. „Ontogeny of feeding morphology and kinematics in juvenile fishes: a case study of the cottid fish Clinocottus analis“. Journal of Experimental Biology 199, Nr. 9 (01.09.1996): 1961–71. http://dx.doi.org/10.1242/jeb.199.9.1961.
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The development of feeding morphology, kinematics and behavior was examined in the juveniles of the cottid fish Clinocottus analis. The attacks of 18 juvenile C. analis, between 17.59 mm and 42.15 mm in standard length (SL), feeding on brown worms were filmed using high-speed video. Feeding mode, ram- or suction-dominated, kinematic variables and morphology were quantified and compared over the juvenile period. The analysis of these three factors was based on the following questions: (1) do they change over ontogeny; (2) how do their values compare with those of larvae, juveniles and adults of other species; and (3) what is the level of stereotypy, as measured by the variance in these factors, at this stage in ontogeny and does it change? Small C. analis juveniles have the small gape and large buccal cavity of a suction feeder, and this morphology becomes more pronounced as they become larger. The kinematic variables of C. analis juveniles are similar to those of adult suction-feeding cottids and least-squares regression analysis showed significant changes in only two variables (time to prey capture and absolute attack predator­prey distance) over the juvenile period. Feeding mode, as measured by the ram-suction index, shows an increase in the suction component of the strike with increasing size. This study demonstrates that, in C. analis, suction feeding behavior develops during the juvenile period. Within the juvenile stage, morphology, prey-capture kinematics and feeding mode are not tightly linked ontogenetically such that suction-feeder kinematics (short predator­prey distance and low attack velocity) and basic morphology (small gape, large buccal volume) develop much earlier than the employment of a large suction component during the strike.
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Schröcker, Hans-Peter, Manfred L. Husty und J. Michael McCarthy. „Kinematic Mapping Based Assembly Mode Evaluation of Planar Four-Bar Mechanisms“. Journal of Mechanical Design 129, Nr. 9 (21.06.2006): 924–29. http://dx.doi.org/10.1115/1.2747635.
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This paper presents a new method to determine if two task positions used to design a four-bar linkage lie on separate assembly modes (circuits) of a coupler curve, known as an “assembly mode defect.” The proposed approach uses the image space of a kinematic mapping to provide a geometric environment for both the synthesis and analysis of four-bar linkages. The devised algorithm allows assembly mode decisions at an early design stage without resorting to the mechanism dimensions. The numerical effort is low compared to existing solutions.
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Wang, Baofang, Chen Qian und Qingwei Chen. „A Dynamics Controller Design Method for Car-like Mobile Robot Formation Control“. MATEC Web of Conferences 160 (2018): 06003. http://dx.doi.org/10.1051/matecconf/201816006003.
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A dynamics controller design method based on characteristic model is proposed for the formation control problem of car-like mobile robots. Only kinematics controller is not enough for some cases such as the environment is rugged, and the dynamics parameters of the robot are time-varying. Simulation results show that the proposed method can improve the responding speed of the mobile robots and maintain high formation accuracy. First, we obtain the kinematic error state equations according to the leader-follower method. A kinematics controller is designed and the stability is proved by Lyapunov theory. Then the characteristic model of the dynamics inner loop is established. A sliding mode controller is designed based on the second order discrete model, and the stability of the closed-loop system is analyzed. Finally, simulations are designed in MATLAB and Microsoft Robotics Developer Studio 4 (MRDS) to verify the effectiveness of the proposed method.
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Song, Meng Jun, Cheng Jun Ding, Xu Long Wang, Hai Song Zhou, Yi Zhou und Ming Lu Zhang. „Kinematic Research of the Multi-Motion Pattern Bionic Mechanism“. Applied Mechanics and Materials 602-605 (August 2014): 1476–80. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.1476.
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In this paper, a new multi-motion pattern bionic robot was proposed by us. Though we analyzed the robot as a hybrid series-parallel mechanism, the robot is a wheeled-legged robot, and a new methods for constructing the kinematic model of the special four-bar mechanism of the robot very quickly and efficiently was introduced. Then, the kinematic model of the parallel mechanism of the multi-motion mode bionic robot was constructed when the robot was in the stance phase.
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Kumar, Pardeep, und Roshan Lal. „Stability of two superposed viscous-viscoelastic fluids“. Thermal Science 9, Nr. 2 (2005): 87–95. http://dx.doi.org/10.2298/tsci0502087k.
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The Rayleigh-Taylor instability of a Newtonian viscous fluid overlying a Rivlin-Ericksen viscoelastic fluid is considered. Upon application of normal mode technique, the dispersion relation is obtained. As in both Newtonian viscous-viscous fluids the system is stable in the potentially stable case and unstable in the potentially unstable case, this holds for the present problem also. The behavior of growth rates with respect to kinematic viscosity and kinematic viscoelasticity parameters are examined numerically and it is found that both kinematic viscosity and kinematic viscoelasticity have stabilizing effect.
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Gao, Peng Fei, Wei Fang Wang und Dong Hui Wen. „Uniformity of Kinematic Trajectory with Wafer Driving Initiatively in Plane Lapping Process“. Advanced Materials Research 102-104 (März 2010): 555–58. http://dx.doi.org/10.4028/www.scientific.net/amr.102-104.555.
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This paper analyses the kinetic trajectory of abrasives both in initiative driving mode and passive driving mode, and the uniformity of lapping trajectory of the two opposite drive modes is discussed, respectively. The imperative relation between the kinematic trajectory and the uniformity is researched in this paper, as well as the simulation of the lapping trajectory.
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Stepinski, T. „Kinematic Dynamo in Turbulent Circumstellar Disks“. Symposium - International Astronomical Union 157 (1993): 203–7. http://dx.doi.org/10.1017/s0074180900174121.
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Many circumstellar disks associated with objects ranging from protoplanetary nebulae to accretion disks around compact stars allow for the generation of magnetic fields by an αω dynamo. We have applied kinematic dynamo formalism to geometrically thin accretion disks. We calculate, in the framework of an adiabatic approximation, the normal mode solutions for dynamos operating in disks around compact stars. We then describe the criteria for a viable dynamo in protoplanetary nebulae, and discuss the particular features that make accretion disk dynamos different from planetary, stellar, and galactic dynamos.
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Bian, Hui Hui, und Zhong Hua Wang. „Attitude Control of Rigid Body Using Sliding Mode Control“. Advanced Materials Research 383-390 (November 2011): 7550–55. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.7550.
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In this paper, a sliding mode controller is developed based on the modified rodrigues parameters. Modified rodrigues parameters can avoid the singularity in kinematic equations and realize less parameters setting. Finally, the numerical simulation results show that the method is effective.
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Xiong, Ling Hua, und Zhe Si Zhang. „Transmission Characteristics Analysis of Spherical Hinge with Clearance“. Applied Mechanics and Materials 701-702 (Dezember 2014): 803–6. http://dx.doi.org/10.4028/www.scientific.net/amm.701-702.803.
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Spherical hinge as a kinematic pair is widely used in mechanical engineering, but clearance inevitably exists in it and reduces the run precision of the mechanical system. In this paper, two-mode theory of nonlinear spring-damper contact force and modified Coulomb friction model are used for creating a virtual prototype model of a kinematic pair with clearance. Drive force is calculated in 4 kinds of working conditions, 3 different sizes of clearance. Influence of the clearance on accuracy of the transmission force is discussed.
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Tian, Jian Ying, Pei Yu Li, Ya Ping Li und Hong Hua Zhao. „Posture Control of a Reconfigurable Mobile Vehicle with Legged Mode“. Applied Mechanics and Materials 541-542 (März 2014): 1049–52. http://dx.doi.org/10.4028/www.scientific.net/amm.541-542.1049.
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Aiming at the moving requests of the miniature mobile vehicle under the environment of indoors and outdoors, A small track-wheel-legged mobile vehicle was developed in this paper. Many desired locomotion modes such as wheeled, tracked and legged locomotion can be realized by utilizing its independently actuated arms up and down. In order to have good adaptability, high maneuverability of obstacle negotiation and high locomotion security, the kinematic modelling was described, kinematic equations were derived, and optimization control was realized based on the analysis of the stability characteristics with wheel-legged locomotion, which can realize the posture control of mobile vehicle, so that the vehicle has the abilities of maintaining relatively stability of the body over uneven ground,. and these abilities are of great significance to stable operation and vision control of the vehicle.
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Li, Dian, Sheng Guo und Haibo Qu. „A novel multiple working modes parallel mechanism with variable workspace“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, Nr. 1 (25.10.2018): 211–24. http://dx.doi.org/10.1177/0954406218806016.
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In this paper, a novel three-degrees-of-freedom multiple working modes parallel mechanism with variable workspace is proposed. Several studies including kinematic and prescribed trajectory planning are performed. First, the degrees of freedom of mechanism's two working modes are calculated based on screw theory. A prototype made by 3D printer also has been developed. Then, the inverse/forward kinematics and Jacobian matrices are obtained. The workspace and singularity are also analyzed, which show that the proposed parallel mechanism possesses singularity-free internal workspace. Finally, a working mode determination method is presented, which can be used to obtain suitable workspace in order to fully contain a prescribed trajectory. An example trajectory is used to verify the reasonability of the proposed method.
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Abid, Hafedh. „Takagi–Sugeno Fuzzy Controller and Sliding Mode Controller for a Nonholonomic Mobile Robot“. Mathematical Problems in Engineering 2021 (18.06.2021): 1–10. http://dx.doi.org/10.1155/2021/7703165.
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This paper focuses on the nonholonomic wheeled mobile robot. We have presented a scheme to develop controllers. Two controllers have been developed. The first concerns the kinematic behavior, while the second relates to the dynamic behavior of the mobile robot. For the kinematic controller, we have used a Takagi–Sugeno fuzzy system to overcome the nonlinearities present in model, whereas for the second controller, we have used the sliding mode approach. The sliding surface has the identical structure as the proportional integral controller. The stability of the system has been proved based on the Lyapunov approach. The simulation results show the efficiency of the proposed control laws.
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Qin, Wu, Wen-Bin Shangguan und Zhihong Yin. „Sliding mode control of double-wishbone active suspension systems based on equivalent 2-degree-of-freedom model“. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, Nr. 13 (26.05.2020): 3164–79. http://dx.doi.org/10.1177/0954407020919588.
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As a critical component of transportation vehicles, active suspension systems (ASSs) have widely attracted attention for their outstanding capability of improving the riding comfort and the maneuverability. However, due to the effects of the suspension kinematic structure and the rubber elements containing bushings and top mount, the practical double-wishbone ASS cannot achieve the desired performance resulting from the control design based on a simple 2-degree-of-freedom (DOF) model. In this paper, a sliding mode control (SMC) based on an equivalent 2-DOF model is proposed to suppress the sprung mass vibration of a double-wishbone ASS, which is to improve the riding comfort of vehicle. The SMC for a double-wishbone ASS is designed in four steps. First, an equivalent 2-DOF model of a double-wishbone ASS, which considers suspension kinematic structure and rubber properties, is established. The parameter values of an equivalent 2-DOF model are identified by using least square method. Second, an SMC is designed for an equivalent 2-DOF model, and the effect of the parameter value of the 2-DOF model on the riding comfort is investigated by experimental results. Third, a control compensator for a double-wishbone ASS is developed by considering the suspension kinematic structure. Four, the control for double-wishbone ASS is obtained by integrating the compensator into the SMC based on the equivalent 2-DOF model. The numerical simulation results show that the control can effectively suppress the sprung mass vibration of the double-wishbone ASS when the SMC design is based on an equivalent 2-DOF model.
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Ćwiklak, Janusz, Kamil Krasuski und Marek Grzegorzewski. „Reliability Test of a GNSS Onboard Receiver in the Kinematic Mode“. Annual of Navigation 26, Nr. 1 (01.12.2019): 106–13. http://dx.doi.org/10.1515/aon-2019-0011.
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Abstract The article presents the results of the aircraft Cessna 172 positioning based on navigation solutions in the GPS and EGNOS (SBAS) tracking mode. The article makes a comparison of coordinate readings of the Cessna 172 in the ellipsoidal BLh frame. The verification of the coordinates of the aircraft Cessna 172 was used to assess the reliability of the GNSS satellite technique in aviation. In a research test, the navigation data were recorded by the onboard receiver Thales Mobile Mapper during an air test performed over the military aerodrome EPDE in Dęblin. Judging by the conducted investigations, it is possible to conclude that the difference in BLh coordinates of the aircraft Cessna 172 on the basis of the GPS solution and EGNOS (SBAS) solution equals, respectively: from −0.5 m to +3 m for component B; and from −2 m to +6 m for component L; from approximately −11 m to over +1 m for component h. In addition, the paper defines factors of dilution of precision PDOP, based on the GPS and EGNOS (SBAS) solutions. The average value of the PDOP coefficient for a solution in the tracking GPS mode was 2.7, whereas in the EGNOS (SBAS) tracking mode, it was equal to 2.8.
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Kornienko, L. S., Nikolai V. Kravtsov, A. V. Kir'yanov, Vladimir A. Sidorov und Yu P. Yatsenko. „Continuous-wave YAG:Nd laser with simultaneous passive and kinematic mode locking“. Soviet Journal of Quantum Electronics 17, Nr. 2 (28.02.1987): 267–68. http://dx.doi.org/10.1070/qe1987v017n02abeh007563.
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Chen, Yao, Linzi Fan und Jian Feng. „Kinematic of symmetric deployable scissor-hinge structures with integral mechanism mode“. Computers & Structures 191 (Oktober 2017): 140–52. http://dx.doi.org/10.1016/j.compstruc.2017.06.006.
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Xie, Ou, Qixin Zhu, Lin Shen und Kun Ren. „Kinematic study on a self-propelled bionic underwater robot with undulation and jet propulsion modes“. Robotica 36, Nr. 11 (30.07.2018): 1613–26. http://dx.doi.org/10.1017/s0263574718000590.
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SUMMARYThis paper proposed a novel type of bionic underwater robot (BUR). The undulation and jet propulsion modes on the self-propelled BUR were combined, and the kinematic characteristics of the two propulsion modes were thoroughly compared. First, the prototype and swimming strategy of the BUR were presented, and a dynamic model of the BUR was established based on several assumptions. Then, a central pattern generator (CPG) model allowing free adjustment of frequency and amplitude was employed to achieve the undulation propulsion of carangiform fish and the jet propulsion of jellyfish. Also, the kinematic characteristics of the two propulsion modes were investigated through experiments under different caudal fin actuation parameters. The experimental results indicate that the developed prototype can realize the undulation and jet propulsion by the means of the coordinated movement of the multi-caudal fins. By adjusting the CPG parameters, the BUR can switch the propulsion mode smoothly. Furthermore, the propulsion velocity of the BUR initially increased rapidly with the frequency and then slowed down when the frequency was greater than 0.8 Hz in both propulsion modes. The undulation propulsion velocity increased with the amplitude in the measurement ranges, however, the jet propulsion velocity initially increased quickly with the amplitude and then kept constant and even decreased when the amplitude was greater than 11 cm. Under the same caudal fin actuation parameters, the average velocity in undulation propulsion mode was higher than that in jet propulsion mode.